Should be in technical but will get a wider audience here, I thionk.
Anybody got any magic potion handed down through the family.
I'm trying to get some aluminium pistons out of steel liners. I don't think they've moved for 30 yrs but are getting hard to obtain now.
I've tried most of the usuals, and I've got one out. So, I've tried plus gas, derv, coca cola and any other unguents I have around the garage.
One has come out, and one has brought the liner out with it. That one I can, at least, put in the vice to work on but even heating up the liner with Oxy/Axy and using a piece of 3X2 down the bore with a 3lb hammer hasn't moved it.
I've put a scrap piston in Hydrochloric acid but when the smoke dies down, the piston is ok but just the oil seems to have been dissolved. I'd really like to free the piston rings as well.
Any of Granpa's remedies out there ?
I'll be back at teatime to check !
Ted
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>> I've tried plus gas, derv, coca cola and any other unguents I have around the garage.
Vinegar?
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You've got bad eyesight, and you have coke and hydrachloric acid knocking about the house.
Remind me not to come round for a drink.
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I really really must get around to seeing that specialist you know, I read that header as Pist n' Broke!
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Time may be part of the answer.
Penetrating fluid may work, but it could take several applications over several days, or even a week or two.
Last edited by: Iffy on Fri 1 Oct 10 at 13:39
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If the aluminium has oxidised at the contact point with the steel, it might be worth trying some aklaine solution such as drain cleaner, bleach or bicarbonate of soda.
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How big is the oven?
A couple of hours at 160 should crack it free,
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Do you want the liner? If not, make a slot (nearly but not right through along the trapped piston!) all along the liner with an angle grinder, then whack a cold chisel in to "spring" it.
You could try heat/cold. Bung up the "top" end of the liner with glass or rockwool (you can find some in your attic, it's surprising how many households keep some there). Put the whole lot in the oven at Gas Mark 5 (the temperatura at which spit will just bounce off) for 20 minutes. Get it out, wrap it up quick before it cools, prop it up, drop some crushed ice down into the upturned piston, don't over-fill and cool the liner, then when the piston's cooled a bit whap it out using a steel drift on a thick piece of scrap steel or a steel pipe stop-end "upside-down". The packing needs to be near bore-size or you risk holing the piston. I've done some old motorbike pistons like that.
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Yeah....shower of comedians......I love you all !
Tried a bigger hammer BB....sledge hammer..was in danger of knocking the vice off the bench !
I thought about cutting the liner, but I really want to keep them...more so than the pistond, although both would be better.
I couldn't get the blocks in the oven...was a thought but I'd have hoped the welding heat around the liner that has come out would have done the trick.....maybe try again and this time put ice in the piston as Fothers suggested.
ATM I've poured the acid into the piston..outdoors... and am going to leave it in for the weekend. When the fumes cleared, the whole liner was bubbling over with a filthy grey sludge.......hopefully the carbon being got at round the back of the rings. The acid had no effect on my scrap piston so the metal should be ok.
Z...It's all quite safe....you're welcome to come for a drink. The Acid is kept safe in a big plastic bottle with a red laber saying C...........or is it the other way round ?
Anyway, I've spent the afternoon tidying the workshop ready for the next onslaught !
Thanks all.
Ted
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Vinegar worked for me on a XJ6 head.
Took 4 days tho.
WD40 protects the corrosion so a complete no-no...
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Yes, the rings and liner have become one... Anything that will soften rust. I thought penetrating oil, in quantity, left for days.
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I agree time is needed.
When separating the pistons from the barrels on a Triumph 650 twin that had been standing for 20 years, we filled the top part of the barrels with Plusgas and left it for a week. A couple of sharp taps with a hammer then freed them off.
We'd tried shorter intervals with no joy.
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& then the metal from the two faces have diffused into each other...
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I don't think so MM. I have managed to remove one piston and there's no damage to the either the bore, rings or piston.
I think I'll leave them for another couple of weeks, that'll make a month but there's no rush. i'm just building up a spare engine, which I'll then put in the car and use the current engine as a spare. I'll see what the acid has done by Monday....they might just tap out !....I wish.
Meanwhile I've got a couple of heads to get sorted and all the ferrous part to get prepared and sprayed.......no lack of things to get on with !
Ted
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I made some notes of old wives and slightly more technical methods when Mart's 'glow plug fault that wasn't' thread got me thinking for the future.
Someone used Iodine, and other suggested Cillit Bang.
One suggestion came up for Loctite's Freeze and Release spray which is supposed to freeze the item down to a very lower temp hopefully shrinking the thing your aiming at...
make sure you've got a couple of pairs of Y fronts on then..;)
I looked this stuff up, it's around a tenner for a spray can but found it on the usual place for about £7...whether it will do the job i know not.
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>> Someone used Iodine, and other suggested Cillit Bang.
Bang! And the pistons gone...
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Can't you rig something up with a hydraulic bottle jack just to get things moving?
Kevin...
Last edited by: Kevin on Fri 1 Oct 10 at 20:39
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Nothing to secure the jack, Im afraid.
The pistons have to come out upwards due to castings in the crankcases so you can't hammer the piston tops.......there's nowhere for them to go/
Ted
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But hammering them down a bit might free them to slide out upwards.
Wouldn't it also give you a larger area to strike with a block of wood?
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Tried that, Tom.......the 2 remaining in the blocks are at the bottom anyway. Thought if I could move them down a tad, I could then clean the cylinder wall and oil it....but no luck.
The only way to hammer them up is to hit the end of the con-rod with the copper hammer.
That's what brought the other two out...although one came out with it's liner....and is solid in that liner. I'm not too happy doing that, but I've plenty of con-rods.
The piston that came out shows no sign of any rust on the compression rings and there's only a light coating on the liner wall.
I'm inclined to think they're just ' gummed ' up....but solidly !
Still...it's a challenge and I'd only be sat in the parlour scowling at Erin Dors !
Ted
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One option if you can't fit them into the oven is to get hold of an old oil drum, make a nice bondfire out of wood and some smokeless fuel (burns at a higher temp).
When that's burning nicely drop the liner with piston in there on a chain if you can. When it's up to temp - bring it out, set it up and try to knock the piston out.
Or just use the barbeque :)
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Ted: time, with lots of solvent-loaded penetrating oil, Plusgas or similar, even Redex.
Then, after several days, pour the oil out and play a fairly fierce and hot flame on the liner all round, for long enough to expand the metal. Then, and only then, immediately try the wood block and big hammer, without doing damage.
If it still doesn't move, repeat whole cycle. You can move it perhaps without doing irreparable damage to the piston.
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Is it me or are these 'removal' methods getting a bit technical??
M
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M
Did you drive your van here?
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I wouldn't like to put an alloy engine block in a fire.......distort all the bearing seatings.
Good scheme AC but you can't get the flame near the liners......they are tightly enclosed in the alloy housing below the water jacket.
Looks like ' soak and wait ' several times.......you never know, Monday might show a result.
Ted
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Hows about giving Sarsaparilla a go, most efficacious in every way,
If it nay works you could always drink the remainder!
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Only allowed diet...if it's available. Do get a bottle of diet D & B sometimes.
Having left the three pistons over the weekend with Hydrochloric acid in, I cleaned them up and had another bash. The two that are stuck in the liners in the engine still wont move, but I had put the acid in the top, on the crowns of the pistons.
The third, stuck in it's liner, but out of the casing, had been dosed actually in the piston.
I put this one back in the vice, horizontally, and attacked the piston crown with a length of 3X2 softwood and the copper hammer. After a few hefty smites, I detected a millimetre deep ring of clean piston at the bottom of the liner.
I went upmarket and got the 3lb lump hammer to work, managing to get about 13 mm showing. So I oiled the bore above the piston and hammered it back, using the big-end and resting the top of the liner on the floor.....It moved ! I got it to a fairly loose stage, put it back in the vice and gently drove it out. That's 2 done.
The bore is excellent and the chrome compression rings show no sign of rust or pitting of any sort.
This leaves me to think that they are stuck by 30 yrs of solid deposits around the oil scraper, rather than rust, and putting the acid in the piston has allowed it to seep through into the ring.
I've got the other 2 now filled as that one was....I'll leave it a week or so.
I dont think I'll be able to rescue the rings but they may be available and I've got a box of various ones, and some on other pistons, anyway.
The fun starts getting the other three liners out, there's nowhere to hammer them and they break easily, being cast steel. The club's liner extracting tool is somewhere in the country but nobody quite knows who's got it !
Ted
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Piston broke. - VxFan
